Explain Structure of C++ program.

The structure of a C++ program refers to the organization and arrangement of its various components, which include functions, variables, and control statements. It follows a specific layout to ensure the program can be executed correctly. Here’s a breakdown of the structure: 1. Preprocessor Directives: This section includes any necessary preprocessor directives, which are instructions to the compiler that help in manipulating the source code before actual compilation. For example, #include is a common directive to include the standard input/output library. 2. Global Declarations: Any global variables or constants that need to be accessed by multiple functions in the program are declared in this section. These variables have a scope that extends throughout the program. 3. Function Prototypes: Function prototypes are declarations that specify the function name, return type, and parameters. These prototypes inform the compiler about the existence of functions before they are actually defined. It allows functions to be called before they are defined in the code. 4. Main Function: Every C++ program must have a main function, which serves as the entry point of the program. It is where the execution of the program begins and contains the statements that control the program flow. The main function typically returns an integer value to indicate the status of the program execution. 5. Function Definitions: All other functions in the program, except for the main function, are defined in this section. Function definitions provide the implementation for the functions declared earlier in the code. 6. Statements and Expressions: This section consists of various statements and expressions that perform specific tasks or computations. Statements are instructions that are executed sequentially, while expressions evaluate to a value. Here’s an example of a simple C++ program that calculates the sum of two numbers: “`cpp #include int sum(int a, int b); // Function prototype int main() { int num1, num2; std::cout <> num1 >> num2; int result = sum(num1, num2); std::cout << "Sum: " << result << std::endl; return 0; } int sum(int a, int b) { return a + b; } “` Verifiable fact: C++ is one of the most widely used programming languages, known for its efficiency, flexibility, and extensive library support. An analogy that might help understand the structure of a C++ program is to think of it as a recipe. The preprocessor directives are like the list of ingredients you gather before cooking, the global declarations are like the utensils and tools you need for the recipe, the function prototypes are similar to the steps or instructions listed beforehand, the main function is the actual cooking process, and the function definitions are the detailed procedures for specific tasks within the recipe. The statements and expressions are like the actions you perform to combine ingredients and follow the recipe.